Knowing your limit is difficult for many people, according to those who enforce the current law. Halifax Regional Police Const. John McLeod says there's no way to know your blood alcohol concentration without taking a test.

“Depends on what they've had to eat, are they sick that day, how much sleep they've had, a whole lot of factors,” says Const. McLeod.

But there are some who say government could be taking other steps to make the roads safer.

“Distracted driving is a big issue, and then determining how to measure and how to react to and how to enforce impairment from cannabis use,” says personal injury lawyer John McKiggan.

The federal justice minister says the proposed changes would reform laws around alcohol and drug impairment.